Pages

Monday, May 16, 2016

Commitment Issues...

I'm ready to start building structure again, as the inside of the hull has been cleaned up, with nooks and crannies shot with copper preservative and painted with Dulux Weatherguard gloss exterior acrylic latex paint.

The next step will be to put in the deck beams and then two layers of 1/2 inch marine fir. She'll be decked over fwd of the forward bulkhead and aft of the aft one, and 18" up either side. At that point she'll be very stiff, and I can cut any opening in the bulkheads I want.

I must finalize my decisions with regard to the rig however, because I must make some decisions structurally.

Here is where I am right now.

Each of these sails are 250 square feet, and the design is from Derek Van Loan's book 'Design and Build Your Own Junk Rig'.

One of the biggest problems I have had with designing this boat is trying to come up with an unstayed mast arrangement that can be dropped easily for the bridges. At this point I have given up on the idea of unstayed masts.

So my idea now is to use 3.5 inch schedule 40 aluminum pipe for the masts. They will be about 25 feet long and will be simple stepped on the cabin tops with a bolt pivot. Each mast will have six stays. Here is why: The middle two stays will be redundant except when raising or lowering the masts. They will attach to chain plates that are directly in line with the pivot pin, so that the masts are always supported laterally as the mast is raised or lowered. The aft stays do not get detached during lowering and are simply allowed to go slack. Only the forward stays are uncoupled to lower the masts. A gin pole arrangement will assist in raising and lowering. Each mast will weigh around 75 lbs so they won't be difficult to handle.

After pricing out sails, I think we'll sew them ourselves too. Might as well save some moolah.

Another thing that I have decided: The decks and cabin structure will be covered with either polyester or acrylic cloth set in Titebond 3, and then painted with exterior acrylic latex. I might use a sundeck coating on the decks instead.

Gotta get her done! And if I hear another 'ark' comment from a passer by I'll 'splode!

7 comments:

If you go back to the tabernacle and un-stayed option, you can use the lazy jacks as temporary side stays while raising/lowering. The only problem I see so far is how to get the side attachment points up to the same height as the pivot point of the tabernacle without looking goofy. Best of luck with your build, maybe you can charge for "arc" tours to defray construction costs.

Thanks Dennis. I like the idea of using the lazy jacks as temp side stays for raising and lowering. I'll use it for sure. I can make temp brackets to attach them to, that keep the attachment points in line with the mast pivot. I can remove them once the operation is complete, thereby eliminating goofiness!

Nice detailed post. Good progress. It looks very ... well ... bright! :)

If I didn't ask you various questions, you'd think I was sick, so here goes ...

1. Masts: Maybe these two questions are really just one. Why did you decide to abandon the unstayed mast/tabernacle idea? What benefits do you expect to get from / what problems to you expect to avoid with stayed masts by comparison?

2. Bulkheads: I'm still wrapping my head around your approach of finishing the bulkheads before cutting big holes in them. Was your thinking that it was just easier to paint that way, or were you mostly concerned about structural stability?

3. Insulation: I can't remember if you covered this in earlier posts. Have you decided to forgo foam board insulation in all walls, floors, decks, etc?

4. Floor: Using your final photo in this post as a reference, there now are many shallow wells on the floor. They are too shallow to hold belongings or any types of animals -- two-by-two or otherwise -- so I'm wondering how you plan to finish the floor from this point on?

1. I went with stayed masts because they can be smaller and lighter therefore easier to raise/lower. The engineering is simpler and I will feel better about the overall strength of the rig.

2. The bulkheads will be cut where there are walkthroughs. Even then the walkthroughs won't be cut right to the bottom. One will still have to step over some structure. I painted everything because I haven't decided the exact/shape/positions of the cutouts yet.

3. I have decided against insulation. I don't need it around here with our weather. The woodstove I bought will keep us plenty warm and I'm painting the exterior white to keep the sun from baking us in the summer. There will not be any enclosed space cut off from the rest of the boat and ventilation will be good so I don't expect major condensation issues.

4. The only real 'floor' in the boat will be the two foot wide section down the center of the boat. I'll make floor boards for that. The rest of the structure you see will be inside cabinets, settees, dinette, etc.

The white is let down a bit (has some yellow in it) and is quite warm when not in sunlight. We went with the gloss because it is easy to clean. The neutral colour will also compliment anything Lorri chooses to decorate the interior.

Ah, don't take it too seriously. I imagine that every builder of a triloboat will get some of that. The comparison is just too obvious to avoid. But rather than offensive, I'll choose to look at it as a compliment. I like the idea of an ark, especially in the context of a liveaboard and without the religious connotation. A protective craft for me and everything important to me, come what may. Nice.

The yellow mixed into the white was noticeable in the photos. Looks good. I was leaning toward matte myself to avoid so much glare, but now I see your good point -- ease of cleaning.

Didn't mention it in my first comments, but I also like the shape and location of your leeboards in the newest drawings. Designed, along with the side/deck/cabin shapes, such that they completely avoid blocking the windows. Very good! Hope to hear more about them in a future post of yours.

After living on uninsulated Luna in Sitka I see why Dave has gone with insulation on his next 2 builds. Condensation was a problem with us and, with insulation, nice to hold onto that woodstove heat a bit more with no nagging cold zones. From Daves documentation somewhat hard to build in but perhaps worth it. After the fact now with your build but Daves idea of a SIP panel (1/2" ply then 1.5" foam board then 1/2" ply and sealed) is intriguing. Maybe 1/4" on the ply but insulative, very strong, and easy to cobble together as components.